Lockheed Martin Corp.'s new $31 billion helicopter for the Marine Corps may be falling behind schedule and could miss its target for initial combat capability by as much as eight months, Pentagon analysts say.

Defense Department officials are tracking more than 1,000 current or projected "mission-impacting technical issues" that present "a high risk" to the CH-53K helicopter meeting its December 2019 goal, according to a program review document.

The Navy plans to buy 200 of the copters known as the King Stallion. The aircraft, scheduled to make its international debut this week at the annual air show in Berlin, was a prime motivation for Lockheed's $9 billion acquisition of Sikorsky Aircraft from United Technologies Corp. in 2015.

Fixing the flaws has required the "redesign and re-qualification" of a "significant number of components," according to the review prepared in February. Four helicopters in a flight test program were operating at 69 percent effectiveness as of late last year, "well below" the 75 percent to 90 percent benchmark needed, the review found.

James Geurts, the Navy's assistant secretary for acquisition, "believes we are at a critical phase" and "the next several weeks will be key," according to a statement by the service. Geurts recently met with Lockheed and Navy program officials "to discuss his concern about the testing schedule as planned" and "expressed his sense of urgency to improve" the situation.

The King Stallion will be capable of lifting 27,000 pounds. It will be the same size as its predecessor, the Super Stallion, but able to haul triple the cargo, according to Lockheed. The Pentagon in April 2017 approved the program entering low-rate production, authorizing production of the initial batch of 26 helicopters.

Melissa Chadwick, a spokeswoman for Bethesda, Md.-based Lockheed, defended the helicopter's progress, saying in an email that "we are tracking to plan plus-or-minus a bit." She said the contractor is tracking about 100 items "and all but a few are either already fixed and proven or are in process."

She said "the program is maturing rapidly, and we remain committed to enabling" the Marine Corps to "complete operational test requirements on schedule. Further, we are on target to enter into production."

The first CH-53K, a test model, will be delivered next month to Marine Corps Air Station New River in Jacksonville, N.C., she said. Fixes to the copter's main gearbox "drove early schedule issues leading to first flight," but "the balance of qualification testing" of the gearbox "is proceeding per plan," Chadwick said.

The Navy's budget plan for fiscal 2019-2023 calls for increasing procurement spending on the CH-53K to $2.3 billion in 2023, up from $756 million this year and $1.3 billion proposed for fiscal 2019.

The Navy's latest Selected Acquisition Report on the helicopter acknowledges its problems but says the chopper remains on schedule to meet its milestones. Still, it found that "efficient resolution of technical issues" and incorporating design changes "will be critical to meeting" the program's schedule.

The current projected acquisition cost, including development, is $139.5 million per aircraft, according to the acquisition report. That's 20 percent more than the original baseline set in 2005. A 1982 law would require notifying Congress if the overrun reaches 30 percent of the baseline or more.

Greg Kuntz, a spokesman for the Naval Air Systems Command, said there's been no formal change in the date for initial operational capability, but the program office is completing a new review of the schedule risk.